Gas turbine fuel regulator with manual and temperature responsive means to select fuelair ratio



P- WL WYCKOFF June 3, 1952 2,599,507 ANUAL, AND TEMPERATURE GAS. TURBINE FUEL REGULATOR WITH NI RESPONSIVE MEANS TO SELECT FUEL-AIR RATIO Filed July 25, y194??4 3 Sheets-Sheet l IN VEN TOR. )ZezzZ /44 /Wgc/f off.' BY

WN WN .MNE

June 3, 1952 P. w. wYcKoFF GAs TURBINE EUEL REGULATOR wITR MANUAL AND TEMPERATURE RESPONSIVE MEANS To SELECT FUEL-AIR RATIO 3 Sheets-Sheet 2 Filed July 25, 194'? INVENTOR. @ai /7/ 9c/Iam By June 3 1952 P. w. wYcKoFF 2,599,507

@As TUREINE FUEL REGULATOR ywTTN MANUAL AND TEMPERATURE RESPONSIVE MEANS To SELECT FUEL-ATR RATIO A Filed July 25,'194'7 3 Sheets-Sheet 3 Afa - IN VEN TOR. 2/5 75a] /4/ Mge/ off.'

a plurality of controls. In the conduit means |9 is positioned a plurality of elements 39 responsive to temperature of the air passing from the regenerator I2 to the burners |3. The temperature-responsive elements 39 exert a control over the fuel-metering device 31 diagrammatically illustrated in Fig. 1 by the line 40. Each air scoop I6 carries conventional elements 4| and 42 for measuring the rate of air flow through the scoop; the air pressures acting upon these elements are transmitted to the fuel-metering device 31 by lines 43 and 44. Adjacent the inlet to the gas turbine |4 is a temperature-responsive element 45, which measures the temperature of the gases entering the turbine. This temperature element 45 acts through a means diagrammatically illustrated by the line 46 leading to the lines 43 and 44 to modify the air pressures transmitted from the air measuring elements 4| and 42 in the air scoop |6. The various controls just described as acting upon the fuel-metering device 31 will now be described in greater detail. In Fig. 2 the fuelmetering device 31 is seen to include a body 41 having a large hollow end 48 divided into a plurality of chambers by diaphragms 49, 50, and 5|.

The effective area of the diaphragm is shown to be considerably larger than that of each of the diaphragms 49 and 5|, and may, for example, be twice as large. The diaphragm 50 has an orifice 50a at its lower side. Contactors 52 and 53 are attached to opposite sides of the central diaphragm 50 at its center so as to abut the diaphragms 49 and 5|. An intermediate portion of the body 41 has a chamber 54 in which is mounted a servo-container 55. is formed of mating halves 56 and 51 of approximately concavo-convex shape. The container is secured to an intermediate wall of the body 41 by means of a plurality of bolts 58, only one of which is shown. The container has a tubular extension 59 projecting to adjacency with the diaphragm 5| and providing an outlet from the container. The container outlet is variably restricted by the diaphragm 5|. depending upon its position. The container 55 registering with an auxiliary fuel passage 6| formed in the body 41. The auxiliary. fuel passage 6| branches from a main fuel passage 62 which leads to a regulating orice or valve formed of a sleeve valve 63 and a piston valve 64 positioned within the sleeve valve and cooperating with it. The right end of the sleeve valve 63 is slotted as indicated at 65 and engages a reinforcement 66 attached to the container 55. The left end of the sleeve valve 63 is enlarged and flanged as indicated at 61 and is engaged by a coil spring 68, which acts between the said enlarged end and one end of a chamber 69 formed in the body 41, to urge the sleeve valve 63 to the right against the container 55. The sleeve valve 63 has an opening 10 in connection with the main fuel passage 62 in the body 41 and openings 1| and 12 which are opposite an annular recess 13 formed in the body 41. From one side of the annular recess 13 extends a passage 14 at which the line 38 leading to the burners is attached. From the other side of the recess 13 there extends a control line 15 to a bypass valve 16. This bypass valve comprises a body 11, a diaphragm 18, a needle valve 19, and a spring 80. The valve 15 is arranged to relieve a pump 8|, which may be of the gear type as shown. The conduit 82 leads from the gear pump 8| to the main fue1 passage 62 in the body 41. A line 83 goes from the conduit 82 on the pressure side of the pump 8| to the bypass valve 16, and a line 84 goes from the This container has an inlet 60 valve 16 to a conduit 85 leading to the intake of the pump 8|. The pressure in the control line 15 leading to the relief valve 16 controls the pressure in the line 83 at which the valve 16 will bypass. The less the pressure in the line 15, the less the pressure in the line 83 need be in order to lift the needle valve 19 from its seat for causing bypassing by overcoming the resistance to lifting of the needle valve imposed by the pressure of the line 15 and diaphragm 18 and the pressure of the spring upon the diaphragm. The pressure in the control line 15 is in turn dependent upon the drop in pressure produced by the restriction offered to the passage of fuel through the opening 12 in the sleeve valve 63 by the piston valve 64.

In the conduit 85 is placed means forming metering orifice 86 for the fuel passing through the conduit 85. Lines 81 and 88 lead from the conduit 85 at opposite sides of the metering orifice 86 to the two outer chambers in the enlarged end 48 of the body 41, transmitting two different fuel pressures to the diaphragms 49 and 5|. The fuel pressures acting against the diaphragms 49 and 5| are opposed by air pressures within the diaphragms 49 and 5| transmitted through lines 89 and 90 leading from pressure-sensing elements 4|.and 42 in each air scoop I6 as shown in Fig. 1. Line 90 has a variable orice 9| controlled by a needle valve 92, in turn controlled by nitrogenlled bellows 93, which increases in size and provides further restriction of the opening 9| with decrease in air density, thereby providing a density compensation to the air pressure transmitted to the diaphragms 50 and 5| through the line 90. The orifices 50a and 9| combine in action to determine an actual difference of air force acting on diaphragm 50 for a. given air-flow rate in line |6. The bellows 93 is mounted in a hollow member 94 which forms part of the line 89 leading from the pressure-sensing element 42 to the diaphragms. Bypass lines 95 and 96 lead from the lines 89 and 90 to a compensating device 91 which includes the element 45 responsive to temperature of hot gases entering the gas turbine. When this temperature exceeds a predetermined value, a bellows 98 forming part of the element 45 expands sufciently under the action of a iluid within the element 45 to cause a piece 99 to contact and lift a valve |00. This places the lines 95 and 96 in communication with one another and tends to equalize the pressures in the lines 89 and 90 leading to the diaphragms. Thus the air signal to these diaphragms is reduced. A spring I0| urges the valve |00 to closed position.

The element 39, Which has previously been described as responsive to the temperature of the air going from the regenerator I2 to the burners I3, is shown in Fig. 2 to comprise a part |02 exposed to the stream of air passing from the regenerator to the burners, a bellows |03, and a line |04 connecting the part |02 and bellows |03, and uid contained in these members for expanding the bellows |03 as the temperature of the air stream from the regenerator l2 increases. The bellows |03 acts against a valve rod |04 carrying a head portion |05 adapted to vary the restriction of an opening |06 formed in a valve seat |06a formed in a tting |01. Lines |08 and |09 lead to the fuel conduit 85 at opposite sides of the metering orice 86. Diaphragms ||0 and mounted in the fitting |01 keep fuel reaching the fitting |01 by way of the lines |08 and |09 from escaping endwise of the fitting |01.

It will be seen that the orifices 86 and |06 are in parallel with one another and that fuel may pass! through both ofthem. The orifice |06 is decreased in size as the bellows |03 expands in response to an increase of temperature of air passing from the regeneratcr I2 to the burners I3. It may be considered that the orince 86, previouslyv described as beinga metering orifice and the orifice Iii@ may be generally jointly considered as'combining to form a metering orice. This combined metering orifice varies in size in inverse proportion to the temperature of the air leavingthe regenerator I2, since the orifice |85 varies: in this way, and the orifice 8B is shown to be fixed.

The operation of the apparatus thus far described will now be set forth. Fuel travels from the gas tank 33 through the transfer pump 35 to the' orifices BG and |06.. The rate of fuel flow past these orifices is measured by the lines 81' and d? which transmit two different pressures to the outer sides of the' diaphragms e9 and 5|. If the airflow is proper for the fuel flow, then the three diaphragme te, 5u, and 5I'will have a certain position determining a certain restriction of the outlet from the container 55 by way of the tubular extension 5s. The pressures transmitted in the air scoops It by way of the elements il and $2 and the lines BSB and 9D will have a difference appropriate for the difference in fuel pressures transmitted through the lines 8l and SS to the outer sides of the diaphragme 49 and 5i, the dii-I ference in area between the diaphragm 53 and each of diaphragms te and 5I providing the requisite compensation. Thus with the air liow matching the vfuel flow as stated, the resultant positioning of the diaphragms'lifl, 5), and 5i, as shown, causes the diaphragm 5I to provide the aforesaid certainrrestriction of the outlet in the tubular extension 5s of the container E5. Thus the container 55 has an amount of expansion dee termined bythe fuel flowing into the container by way of the passage `ISI and the inlet 5t and the amount of outlet restriction provided by the diaphragm 5I to the tubular extension 59. Accordingly, the container 55 makes the valve sleeve t3 assume a position with respectto the piston valve Eri, and the amount of restriction provided at the opening il in the valve sleeve 63 lets the proper amount of fuel flow' through the conduit line 36 to the burners.

if now the rate of air now through the scoops It changes, for example, decreases, then the difference of the pressures sensed by the elements di and e2 decreases. Thus in effect, the pressure transmitted `by the line 90 to the left side of the middle diaphragm 5l] decreases with respect to the pressure transmitted by the line 89 to the right side of the diaphragm 56. Accordingly, the three diaphragms will move to the left increasing the restriction to the outlet from the container 55 by way of the tubular extension 59, since for the moment, the difference in fuel pressures transmitted by the lines 8l and 88 has remained the same. Increase in the restriction of the outlet from the container 55 expands the container, thereby causing the valve sleeve 63 to move to the left .and the restriction of the opening `II in the valve sleeve 63 to increase. Thus less fuel flows, and the fuel-pressure difference transmitted through the lines Sl and 8B to the diaphragms 49 and 5I decreases. Finally, the final flow will be appropriate for producing a fuel-pressure difference effectively matching the air-pressure difference transmittedto the diaphragms from the sensing elements el and 42, and the diaphragm movement stops, fixing the restriction of the outletof the containerv thersize ofi the'centaine'if.l`

the: position of the. sleeve 53, andthe sizeofrfthe opening therein.

If the air flow in the scoops I6. increasesirom whatit was at the first described condition, their' the difference in pressures transmitted byv thel lines S and 89' to the diaphragmsv increases.E over whatit was at the first describedconditioncaus ing the three diaphragme to' move to: the right'v from the position shownl inS Fig. 2,-respective:.013v the first described condition. Thus ther'restric-f tion of the escape openingv of the' servo-container.

55 is decreased, the container collapses,thessleieve,

valve' E3 is moved to the right 'underf'the action ofthe coil spring 68, and the effective .opening of'. the valve port I in `the' sleeve valvel 6311s ine creased. Thus: there is an increase-in the; fuel; now', which is reflected as' an increase: in fuel.Y pressure differ-ence transmitted by'thez'lines 811 and B8" to the diaphragme 4'9- a'nd 5i, bringingi abouta new position. of the equilibrium.

new position will be somewhat to the right.

the weight of-` fuel should decrease to Aproduceert predetermined temperature of hot; gasesenterinsi the turbine. However, if. there isf no decrease-'in volume of air flow, there is no decrease in pres-'- sure di'ierences transmitted through the ele-f ments HI and 42, which pressuredifference-de-4 termines the rate-of yfuel flow. Thefbellows `93105'- causing the contoured needle valve 92- to restrict the orifice in the line 9B provides a'cornpensation for'A the decrease iii-density air iiowing through the scoops It. As the air density decreases, thebellows 93 expand, causing the needle valve192 *tol increase the restriction in the line 90. Thus thepressure finally transmitted by the linerS totheleft side of the diaphragm '53) is less than the pressure sensed bythe element 4|'. The resultant decrease in pressure transmitted produces an apA propriete decrease in pressure difference acting upon the bellows, and this appropriate decreased pressure diiference acting on the diaphragm produces an appropriatedecreas'e in fuel flow.

"The element 45 responsive to temperature'of hot gases entering the turbine Ill comes into ac tion only when this temperature exceeds a preole-A termined value.l At this time, as previously-deV scribed, the bellows 8- causes the part 99 to liftk the valve `from its seat. Thusthe 1ines95 and SB are placed in communication, and there `is a' tendency to equalize the pressure `inthe lines-89 and 98, dependent upon the restriction in the communication between the lines yand y96- oiiered by the valve |520. This tendency toward equalization `of pressures in the lines rB9 and A9|! means a decrease indifference in airV pressures transmitted tothe diaphragms '49, 5in-nd'v 5I from ythe diiierence` in pressuressensed :by 'thev elements 4I and 42. Thus the'fuel yflow is appro'- priately reduced vto'bring the temperature of 'hot gases entering the turbine down to the desired value;

Let usinoW consider` the eiect of change in the restriction of the orifice |36 vby shifting ofthe valve |05 in response'tochange in temperature of air passing from the -regenerator' VI2 .tothe l'burners` I3. Let us assume that :the temperature of' air delivered from the regenerator lrl increases;

for such a reason as improvement in regenerator efficiency or increase in temperature of air entering the compressor through the scoops I6. The air reaching the burners I3 must now be heated a lesser amount to produce a predetermined temperature at the entrance to the gas turbine. Thus the rate of fuel flow should be decreased for a given rate of air flow. This is accomplished by the temperature-controlled orifice |06. Increase in temperature of air coming from the regenerator I2 .causes the bellows I I3 to expand and thereby.-to move the valve nearer the seat |069. Thus the restriction of the orifice |06 is increased, and less fuel flows through the line 85, since the size of the orice 86 is kept constant. The total effective restriction provided by the orifices 86 and |06 is increased, and thus to maintain a given difference of fuel pressure transmitted through the lines 81 and 8B of the diaphragm to balance acontinuing difference in air pressure transmitted to the diaphragms representative of a given air flow in the scoops |6, the rate of fuel flow must decrease.

`Angular position of the piston valve 64 is controlled by a pilot-operated arm I I 2. Within certain limits the position of the arm I'I2 has no effect upon the temperature of the gases going to the turbine, but beyond this limit there is some effect. It will be observed that the piston valve 64 has an inclined land at the openings 1I and 12 in the valve sleeve 63, which through an angular shift of the valve 64 by the arm I I2 changes the size of the valve openings 1I and 12 for a given position of the valve sleeve 63. Suppose, for example, that the angular position of the valve 64 is changed so as to provide a reduction in the size of the openings 'II and 12 for a given position of the valve sleeve 63. Then less fuel will ow, the fuel pressure difference transmitted through the lines 81 and 88 to the diaphragms will be less, and the diaphragms will move to the right, thereby decreasing the restriction of the outlet in the container 55. This permits the container to collapse to a certain extent, the spring 68 moves the valve sleeve 63 to the right, and the openings 12 and 13 in the valve sleeve 63 are increased in size. Thus the fuel ow is returned to the original value it had before the valve 64 was angularly shifted by the control arm I I2. Since the fuel flow remains the same (and it has been assumed that there has been no change in air flow) there is no change in the temperature of the gases going to the turbine. If the valve 64 is shifted farther through the control arm ||2 to provide further restriction of the openings 1| and 12 in the valve sleeve 63, the servo-container 55 will further collapse. Eventually a point will be reached at which the sleeve valve 63 can no longer follow the container 55 as it collapses, because the flange 61 on the valve sleeve 63 has come into engagement with the right end of the chamber 69. Beyond this point, decrease of the valve openings 1I and 12 through angular shifting of the piston valve 64 by the control arm |'I2 is permanent in the sense that the sleeve valve 63 can no longer shift to compensate for the shift of the piston valve 64, and thus there results a correspondingly permanent reduction in the flow of the fuel and a reduction in the temperature of the gases flowing to the turbine.

There may be also an adjustment of the temperature of the gases flowing into the turbine through a replacement of the means forming the metering orifice 86 by a new means forming an orifice of a different size. If the new orice is larger thanthe old one, the fuel ow there'` through will be greater for a given pressure difference transmited through the lines 81 and 88, the fuel-air ratio will be greater, and the temperature of the gases reaching the turbine will be increased. If the new orifice is smaller than the old one, the opposite effect will take place; the fuel-air ratio will be decreased, and the temperature of gases entering the turbine will be decreased.

Fig. 3 shows another form of apparatus to which the inventive principles of the present application are applied. Reference character ||4 designates a body which may be formed of several parts and through which fuel is passed for regulating purposes. A velocity-pressure-sensing element ||5 is positioned in an air line, for example, the scoop |6 leading to the compressor A line ||6 connects the element ||'5 with the body ||4, the line ||6 having an opening |||ia to an air chamber ||1, formed in the body I I4 below a diaphragm |22. An impact-pressuresensing element II8 is also positioned in the aforementioned air line. The element ||8 is shown to be formed to be part of the body ||4 and includes a pressure-compensating nitrogenfilled bellows II8a mounted on the inside of the top of a container ||9. Bellows ||8EL contains nitrogen at some pressure dependent on conditions such as the spring rate of the bellows and compensates for temperature and pressure. The bellows I I8a contracts with pressure and expands with temperature, and therefore, assumes a p0- sition dependent on density, which is proportional to ratio of pressure to temperature. A valve is connected with the nitrogen bellows H6 and is adjustably positioned by the bellows to establish a restriction in a line |20a transmitting the signal received by the pressure element II8 to an air chamber I2| formed in the body I I4 above the diaphragm |22. Mounted within the body I I4 is an air diaphragm |22. The pressure of air sensed by the element II8 is transmitted to the upper side of this diaphragm, and the pressure sensed by the element |I5 is transmitted to the lower side of the diaphragm. Whenever air is flowing, the pressure on the upper side of the diaphragm |22 will be greater than the pressure on the lower side thereof, and the difference in these pressures is a measure of the square oi' the air flow. The diaphragm |22 is held between a collar |24 and a ribbed disk washer |24, mounted upon a rod |25. Above the washer is collar |23, above which is a diaphragm |26, which is secured to bridge portions |21 of the body ||4 by screws |28. The collar |23 and a collar |29 clamp the diaphragm |26. The collar |29 has a recess receiving a nut |30 having threaded engagement with the rod |25. The bridge portions |21 are connected by a cover I3I which extends over the top of the rod |25. Clamped between the diaphragm |26 and the bridge portions |21 is a guide |32 having a ange |33 in which the collar |29 slides. The diaphragm |26 is retained in a flanged support |34, which is clamped to the bridge portions |21 by the screws |28. The collar |24 rests in a diaphragm |35, which closes an opening in a wall |36 dividing the body into an air section and a fuel section. Bolts |31 secure the diaphragm to the wall |36. These bolts also support a guide |38 having a flange |39 receiving a collar |40. Collar |40 holds a diaphragm I4| against a ribbed disk washer I4I, which rests against a shoulder |42 on the rod |25, The various diaphragms and collars Just de- .scribed areheld clamped between the shoulder |42 on the lrod |25 and the nut |30 engaging the upper threaded end of the rod |25. .'Ihe diaphragm |4| divides the fuel section into a metered-fuel chamber |44 and an unmetered-fuel chamber |43. The lower end of the rod |25 is formedas a ball |45, which is mounted ina connecting means |45a,V which also mounts a ball |45h on the upper end of a rod |46. The lower end of the rod |46 has a threaded portion |41 and a slot |48 for adjusting purposes. The threaded portion |41 engages a movable inner sleeve valve |49, which is slidably mounted in a lxedouter sleeve valve |50. The valves |49 and |50 comprise an adjustable regullating orifice |50.

Y The outer valve |50 has an inner annular recess an outer annular recess |52, and Vconnecting radial openings |53. As kshown in Fig. 3, the inner valve |49 partially overlaps the inner .recess |5| of the outer valve so as to restrict the openings formed therein. The outer annular recess |52 of the .outer valve |50 is in registry with -an annular recess |54 formed in the body ||4.

rotary sliding vane type. The pump |60 delivers fuel through the conduit |55 to the recess |54 in `the gbody H4. Thence the fuel proceeds through the regulating orice formed of the sleeves .|49 and |50 to the'unmetered-fuel chamber |44 in the body |4 below the diaphragm |4|.

The unmetered fuel chamber has two outlets for fuel to the metered-fuel chamber |43, comprising orifices |6| and |6|a formed ina wall |63. The effective size of the orifice |6| is controlled by a needle valve |62, the longitudinal position of which is adjustable for variation of the size of the orifice |6|. The needle valve |62 has a threaded portion |63, which is engaged by an internally threaded portion on a gear |64, which isheld against conjoint axial movement with the needle valve |62 by a supporting means |64@ 'which embraces the gear |64. The needle valve |62 is held against rotational movement by means of a square hole in the casing ||4 and a square portion on the needle valve, whichis received by the square hole in the easing. I'he gear |64 is driven by a gear |65, in turn driven by a servomotor |61. The vgear |65 also drives a gear V|66 controlling a potentiometer |68. The 'servomotor |61 andthe potentiometer |68 are suitably connected by wires with an amplifier |66, which is supplied by an electrical source of power |16. The amplier receives a suitable electrical signal through means |1| from an element |12 positioned so as lto be responsive tothe temperature of air flowing to burners supplying a gas turbine. For example, the element |12 may be positioned between the regenerator I2 and the burners I3 inthe conduit 'means I6 in the location of the temperature-responsive element 39 of Fig. l.

'The needle valve |62 regulates the fuel orifice |6| in such a way that the size of the orifice varies inversely withthe temperature of the air supplied to Vtheburners, as measured by the element |12. The signal received through the means |1| from the temperature-sensitive element |12 is suitably magnified by the amplier |69 by the electrical energy received from the source Yof power |16. Changes inthe electrical signal, thus amplified propeller pitch control governor.

cause the servo-.motor |61 to rotate the gear |65. Rotation `of thegear is effective by way of the vgear |64 to provide .longitudinal adjustment of the needle valve |62 `and thereby adjustment of the fuel orifice |6| Rotation of the gear 65 is also effective by way of the gear |66 to adjust the potentiometer |66 to restore the `entire electrical apparatus to balance. In other words. with lthe change in electrical signal, the servomotor |61 will operate to rotate the vgear |65 indefinitely unless compensation is provided in an adjustment of resistance, and this is done through adjustment of the potentiometer |68by the gear |66.

The fuel orifice |6|EL is regulated by means of a longitudinally adjustable needle valve |13, A'to which is connected a .pivotally mounted indicator V14, having a point moving along suitable indicia |15, representing desired temperature of combustion products delivered Aby the burners to the gas turbine. The indicator |14 and needlel valve |13 are shown in a mean position. Movementjof the needle valve to the left, produced by clockwise angular movement of the indicator, jincreases the effective opening of the fuel orifice |6| and thereby increases the temperature to be reached by the products of combustion of vthe burners going to the turbine. Movement offthe needle valve |13 .to the right produced by counterclockwise angular movement of 'the 'indicator j|14 will decrease the .effective opening of the fuel oriiice |61au and thereby decrease-the temperature of the products of combustion produced byi'the burners.

The fuel chambers |43 and |44 above and below the diaphragm |4| are placed in communication Aby a passage |16 formed in the'body |4.a`nd having a restriction |11. Similarly, the Jair chambers |.1 and |2| are placed in communication by a passage i'l formed 'in the body 4||'4 and having a restriction |19. The metered 'fuel chamber |43 is in communication with a 'chamber |16a 'for fuel formed by the cover |.3|, vthe bridge portions |21, and the diaphragm |26. Communication is established through a passage |69 formed in the body l |4 and having a restriction |-8| at the end adjacent the chamber |1911. A passage |82 connects the chamber |16ab with a chamber |86, formed below a diaphragm |84 carying a Yprojection |85 limiting the lower position of the diaphragm |34. Above the diaphragm Y|64 is a chamber |66, which communicates by a line |61 with 'the unmetered fuel chamber |44 through an vopening |86. The lchamber |83`is connected with a chamber |36 positioned below the Wall |66 having an oriice |6| closed bya valve |92, as shown in Fig. 3. Above the wall |60 is a chamber |63, which .communicates through a line |64 with the metered-'fuel chamber |46. The top of the chamber |33 is. formed by a diaphragm |95, which is connected to .the stem of the valve |62 and prevents fuel from going from 'the chamber |63 into a solenoid |96. The solenoid |96 controls the valve |62 through a plunger |61, secured to the stern of the valve |92 in axial alignment therewith. The solenoid |66 is supplied by wires |66a and |961 from a source of electrical power |666. Between the wire i665 and source |66c is connected a speed-responsive switch, which comprises spaced terminals |66d and |666, connected to the line |966, and a contactor at |96f, controlled by a means |66g responsive to turbine speed. More specicallythe means |96g may be associated with the .Propeller 1l speed is directly proportional to turbine speed. The propeller governor is normally arranged so that a 'certain pitch produces a given speed range. Different given speed ranges may be preselected and thus a position of the arm |96f between the contacts |96d and |963 may be produced ,by different selected speed ranges. The arrangement is such that, when the turbine (or propeller) is operating in the desired speed range, the contactor |96f is positioned between the terminals|96d and |96e and out of contact with eachof them so that no current fiows to the solenoid |96. Under this condition, fuel pressure acting upwardly against the diaphragm |93 causes the plunger |91 to be displaced upwards from acentral position in the solenoid |96 and the valve |92 to Vclose the orifice |9l, all as shown in Fig. 3. When the turbine is not operating in the desired speed range, the arm |96f will contact one ofthe terminals |96d and |95e causing current to be supplied to the solenoid |96, which now. moves the plunger |91 downward to a central position and opens the valve |92, placing the 'chambers |89 and |93 in communication. A spring |98 acts against the plunger |91 to urge itdownwardsV and thereby provides compensation for fuel pressure in the fuel chamber |93. The space above the diaphragm |95 is vented by an opening |98. The air chambers ||1 and |2| are connected by a passage |99, which is shown tobe closed by a valve 200. A spring is connected at its right end to the body ||4 below the diaphragm |4| in the unmetered fuel chamber |44. The left end of the spring 20| is engageable with a flange 202 formed onthe connecting means |45*ab so as to provide a yielding limit to upward movement of the stems and |46 and a minimum opening of the regulating orifice |505, formed by the valve |49 and |50. A rod 202EL slidably mounted in the body ||4 may be moved upwardly from the position shown to lift the spring 20| and thereby to remove the lower limit on the size of the regulating orifice |50'-.r The fuel chamber has a drain plug 203.

VA fuel line 204 extends from a region of the metered-fuel chamber |43 immediately to the leftof the fuel orifices |6| and |6|. The line 204 splits into branches 205 and 206, which lead to pumps 201 and 208, which may be of the gear type. A relief line 209 is connected to opposite sides of the pump 201 and contains a relief valve 2|0. The pump 201 discharges through a line 2|| and a check valve 2|2 from which lead lines 2|3 and 2|4. rIhe line 2|4 is formed into two branches 2 |5 and 2 |6. The latter line leads through a valve 2|1 to a flow divider 2|8 from which separate lines go to individual burners. The line 2|5 forms part of a bypass for pump 201 and leads to a valve 2 |9 formed of a body 220, a sleeve 22| positioned therein, a cover 222 and a balanced piston valve 223 slidable within the sleeve 22|. The line 2| 5 leads directly to an annular recess 224 formed in the body 220 about the sleeve 22|. 'Ihe annular recess 224 communicates with the space between sections 225 and 226 of the piston valve 223 by way of passages 221 formed in the sleeve 22|. Passages 228 in the sleeve 22| provide communication from the space between the piston valve sections 225 and 226 and a drain line 229 leading back to the line 206. The drain line 229 carries a float valve 230 for eliminating from the line any trapped fuel vapors. The pump 208 is provided with a relief line 23| which is connected to opposite sides of the pump and carries a relief valve 232. A conduit 233 leads from the discharge side of the pump 208 and separates into two branches 234 and 235. The branch 234 is connected by a check valve 236 with the branch 2|3 associated with the pump 201. The branch 235 leads to the valve body 220 and communicates with the chamber between the piston valve sections 225 and 226 by means of openings 231 formed in the sleeve valve 22 The space above the piston valveA 223 is connected by a line 239 with the conduit 204 and subjects the top side of the piston valve to the fuel pressure in the line 204. A coil spring 239 acts against the top of the piston valve-223 to urge it downwardly. An extension 240 formed on the top of the piston valve 223 limits upward movement of the piston valve. A short extension 24| formed on the lower side of the piston valve 223 limits its downward movement. The space below the piston valve 223 is connected by a line 242 having a restriction 243 to the discharge side of the transfer pump |60. Funda-mentally, the control valve 2|9 for the pumps 201 and 208 operates from the difference in intake and discharge pressures at the apparatus included in body 4, for the upper end of piston valve 2|9 is subjected to the discharge pressure of the apparatus existing in line 204 and the lower end of the piston valve is subjected to the intake pressure of the apparatus existing in line as communicated by line 242. Restriction 243 removes the effect of variations of intake fuel pressure of short duration, and also dampens oscillations of piston valve 2|9 from other causes. Spring 239, acting on the upper end of the piston valve 223 assures that the piston valve assume a certain position along the length of the valve sleeve 22| for a given difference in intake and outlet fuel pressures as transmitted to the ends of the piston valve.

A return line 244 leads from the line 2|5 to the conduit |59V on the intake side of the transfer pump |60. Communication between the lines 2|6 and 244 is regulated by a piston valve 245 under'the control of a speed governor 246 responsive to turbine speed. A relief line 246B containing a'relief valve 241 connects the intake and discharge sides of the transfer pump |60. A line 248 leadsrfrom the line 244 to the valve 2|1. A drain line 249 Vis connected to the valve 2|1. During normal operation the valve 2| 1 passes fuel from the line 2|6 to the fuel divider 2|8. The valve is so constructed that when appropriately regulated, it connects the fiow divider with the line 249 for draining the former and lines 2|6 and 248 for passing the entire flow of fuel to the discharge side of the transfer pump |60.

In operation of the above described apparatus, fuel is drawn from the fuel tank |56 through the booster pump |51 through conduits |58 and |59, the transfer pump |60, and the conduit |55 to the body I4, through which it passes to the annular recess |54 and thence through the orice |53 and annular recesses |5| .and |52 in the outer fixed sleeve valve |50 and past the upper edge of the movable inner sleeve valve |49 to the portion of the unmetered-fuel chamber |44 below the diaphragm |4|. From there the fuel moves to the metered fuel chamber |43 to the left of wall |53 by way of the orifices |6| and |6 l, the sizes of which are regulated in accordance with temperature of air going to the burners, as measured by the element |12, and by desired temperature of products of combustion going from the burners to the gas turbine, as predetermined by an appropriate setvalve |49 ceases.

established, which is appropriate to the new in- 'phragm 14|. the `air-pressure difference acting on the dia- Vjointlyconstitute lmetering-orifice means, andthe pressure of the fuel is reduced in accordance with the lamount of lrestriction `provided at these or'ices'by the needle `valves |52 and|13,'whi`ch "adjust the orifices. y vpressure lis greater than 'the vmetered-fuel 'pres- Since the -unmetered-f-uel v'offuel past the orifices 16| and'il la. 'The upward Het 'fDI'Ce'thIOugh fuel-pressure Adifference acting upon the diaphragm |4| is communicated to 'the krod |25. This'=upward forceonthe rod'is opposed 'by'a downward'force on the rod dependent upon "the difference in lair pressures acting upon 'the Vupper and lowersides of the diaphragm |2-2 in its position, `and there 'is -no change in the -:size of the regulating oriiice formed by the valves |49 .and |59. 'Let lit be assumed, for the moment, that the valve |9'2vis open. If the flow of airt'o the burners changes in rate, this change will be sensed by the elements H5 and H8, .and 'changed difference in pressure will `be Vtransmitted to fthe diaphragm I1-22. If theratefof air flow increases, there will be a Vgreater air pressure dif- 'ference "acting downwardly upon 'the Ydiaphragm |2'2,and for the moment lthe upward fuelfpressure ydifference acting upon vthefdiaphra'gm 54| "will lbe effectively less than the air pressure difference acting upon the diaphragm |22. As a result, the rods `|29 and |46 will move vdownwards causing the upper Vend ofthe movable sleeve valve |49to 'provide less Aof a restriction to 'the'reoesses and passages in the louter fixed valve |50. Thus "there isfan increase in the size of -ltheregulating forice, vand consequently, the flow Vof fuel increases. Since thefuel flow increases, 'the drop in pressure across'the orifices |6|=and 16Mincreases, and thus there is provided a 'greater fuel pressure difference acting upwards upon the diaphragm |41. lWhen the increase in fuel-pressure r 4difference leffectively matches fthe increase in airpressure difference, downward ymovement ofthe valve-rods +25 land A|46 and 'of lthe Yinner sleeve Thus a new fuel flow has been creased air flow. If the air flow decreases, the

Vopposite of fthe above described takes place. vThe ve'ffectii'lt-z lforce of the Yfuel pressure difference acting upwardly upon the diaphragm 4| is greater vthanfthe effective force of theair pressure difference l acting downwardly upon 'the diaphragm |`22,fand therefore, the rods 125 and |49 andthe inner sleeve valve |49 move upwardly. This ac- "tio'ndecreases the size of the regulating orifice formed'by Lthe valve Aparts |59'and 15|, and the fuel -owdecreases Thus the'fue'l-pressure 'drop across `the orices 15| `and |61'l is decreased, and .a lower upward pressureacts against the 'dia- Thus balance is A`restored l'between phragm |22' and the fuel-pressure'difference acting on the diaphragm I4 l.

rvDur-ing the above 'described changes'it has `been presumed that lthe vvalve' |952 -was open, :and 'this 4'was the case if lthe turbine was notin the desired `shift `its position suddenly.

vdiaphragm |84.

speed range, so thatl the'solenoidwas'electricaliy venergized to :bring the core |91V to 'itsflowerposition. Let it 'now be assumed vthat the turbineis operating in the desired speed range. Now the solenoid |96 is no longer energized, and fthe tion under the influence ofthe' fuel pressurelfactv`ing' upwards against 'the diaphragm |195. .'Now

fuel inthe chamber |19a cannot vescape by Way ofthe line |82, chambers |83 and |89, orifice |'9.|,

chamber |93 land line |94, .andltheonly'ioutlet from the :chamber |19a Vis through .the passage |189, but this passage has the vrestriction 18|, which provides a time delay-to such'escape. Thus i the Avolume of vfluid* in the chamber |119lcannot change suddenly, and the diaphragm lioannot Consequently, the rods |25 and |45 and the inner sleeve valve |49 cannot immediately move upwardly or downwardly in Yresponse lto changes in airflow as transmitted as a pressure d'iiference'to .the diaphragm |22. The irods'and valve |49 can/move `lonlyif there is suillcient time for fuel to flow through the restricted orifice |'8| into or out `of thefuel vchamber |19l. Thus changesin airilowfofiashort duratlcnhave no eiect upon 'the 'fuel flow, :for temporarily the inner sleeve valve -I49fremai-ns in its .original position, and there `is no change in the size of the regulating orifice. Keeping the fuel apparatus from being sensitive to air-flow changes of `a short 'duration prevents .unstable operation :of the apparatus, which may easily occur ifthe controls are madesensitive to changes of a short durationin the use of the apparatus 'with the power Aplant shown in Fig. 1.

IIf the-'airflow decreases sufGiently, theirod :|25

'will be urged upwardly withsufcient force Ato cause the Vcompression of the trapped fuel inthe chamber |19a to act against the diaphragrnltlll sufficient-ly to lift it and thereby to provide the appropriate increase in space for the trappedffuel to permit the upward 'movement of theirodsp|f25 `and |46andthe inner sleeve valve |49'for`re`duction of theregulating orifice. Lifting `of .the diaphragm |84 takes place when the pressure in the chamber |19a has through compression ri'sen from-meteredfuel pressure up to .or justLabove the unmetered-fuel pressure existing .above the Thus fora largereduction in air llow there will be immediately provided an appropriate reduction of fuel flow as a'precaution against overheatingof the turbine dueto toov high a'temporary `ratio of fuel-flow rate to lair-flow rate. "The'fuel' flow will not immediatelyfbe reduced completely to the point where the'ra'tio of fuelflow to air flow is the predeterminedvalue, because this ratio can beobtained only when-the fuel pressure in the chamber' |19 is :thefsame as that in fuel chamber ||1, and these pressures will be equal only when suicient fuel has escaped 'from Vthe chamber |19e,'and this requires time.

Aachieve compensation by 'reduction of the 'size of the chamber |93, butlthe projection |85, attached to the -diaphra'gm'prevents downward movement of the diaphragm.

Under 'starting conditions, it may be desirable to use =a lower rate of fuel dow than may beallowed by the minimum 'position established "by the combustion leaving the burners.

`15 idle spring 20|. In this event, the rod 202'* is pushed upwards to raise the spring 20| and thereby to permit the inner sleeve valve |49 to move upwards in response to the air-pressure difference arising from low air flow and thereby reduce the regulating orice to make possible the new desired minimum fuel flow. At other conditions it may be desirable to have a constant fuel flow, for example, a minimum flow permitted by the return of the idle spring 20| to the position shown in Fig. 3, regardless of the air conditions measured by the elements and H8. In this event, the valve 200 is turned 90 from the position shown in Fig. 3 to place the portions of the air chambers ||1 and |2| in direct communication with one another for equalizing as much as possible, the

air pressures on the two sides of the diaphragm It has previously been assumed that the effective size of the metering orice |6| has remained constant, because the temperature of air flowing to the burners has not changed, and therefore, the temperature-responsive element |12 has not acted through various described control means to adjust the longitudinal position of the needle valve |62. If now the temperature of air going to the burners increases, the needle valve |62 is moved to the right, reducing the effective size of the orifice IBI. This means a greater restriction of the fuel owing past the orifices and consequently, a lower fuel-flow rate for a given pressure drop across the orifices. As the size of the orifice |6| is decreased, the pressure drop may, for the moment, increase and this produces an upward movement of the rods |25 and |48 and the valve |49. Thus there is a reduction in flow through the regulating orice formed of the valve parts |50 and |5I, and this reduction in ow brings about a reduction in pressure difference across the orifices |6| and IGIa to obtain a return of the original fuel pressure difference acting on the diaphragm |4| to match the air-pressure difference acting on the diaphragm |22. Thus the rate of air ow has remained the same, but the rate of fuel flow has been decreased as the temperature of air flowing `to the burners has increased. Thus the ratio of fuel to air has decreased, whereby there is provided a suitable balance for the increase of air temperature in maintenance of a constant temperature of products of Decrease in the temperature of air flowing to the burners has the opposite effect. In this case, the needle valve |52 moves to the left increasing the effective opening of the orice I6 Thus the restriction of the flow of fuel across orifices |6| and |6|a is decreased, and there may be a similar pressure drop across these orifices. The decrease in pressure drop is transmitted to the diaphragm |4 which now receives less force to oppose the force applied by air pressure difference to the diaphragm |22, and the rods |25 and |46 and the valve sleeve |49 may move downwards to increase the size of the regulating orifice formed by the valve sleeves |50 and 5|. This produces an increased fuel flow, increasing the pressure drop across the orifices |6| and |6 |8L to restore balance between the fuel-pressure forces acting against the diaphragm |4| and the air-pressure forces acting against the diaphragm |22. Thus the air-flow rate has remained the same, while the fuel ow rate has increased, and so there has been provided an increase in .the ratio of fuel flow to air ow. Thus there is provided a compensation for the decrease in the temperature of air flowing to the burner in 16 maintenance of a constant temperature of products of combustion iiowing from the burners to the turbine.

If a greater temperature is desired for the products ,of combustion passing from the burners to the turbine, indicator |14 is moved in 'a clockwise direction thereby moving the needle valve |13 to the left and increasing the effective size of the orice Ila. Thus, for the moment, the pressure drop across the orifice is reduced for the flow of fuel remains constant, and the fuel-pressure difference acting upwardly against the diaphragm |4| is reduced. Thus the balance between the air-pressure forces and the fuel pressure forces is disturbed, and thus sleeve valve |49 moves downwardly increasing the regulating oriilce formed between the valves |49 and |50. This increases the fuel fiow and the pressure drop across the orifices |6| and Isla. Thus balance is restored between the diaphragms |22 and |4I. The air-flow rate has remained the same, and the fuel fiow rate has increased. Thus there is an increase in the ratio of fuel ow to air flow, and since the temperature of air iiowing to the burners has been assumed to remain constant, the increase in ratio of fuel to air must result in a greater temperature of products of combustion produced by the burner. Similarly the temperature of products of combustion may be reduced by greater restriction of the orifice |6| by the needle valve |13.

After the fuel passes through the metering orices |6| and |6|a, it goes through the conduit 204 to the pumps 201 and 208. If the pump 201 is functioning properly, the entire output of the pump 208 will be bypassed, with the parts in the position shown in Fig. 3, through the openings 231, the space between the piston valve sections 225 and 226, the sleeve openings 228, and the return line 229 back to the intake side of the pump 298. A portion of the output of the pump 201 will be bypassed through the line 2|5, the sleeve openings 221, the space between the piston valve sections 225 and 226, the valve sleeve openings 228, and the return line 229 to the intake side of either pump 208 or pump-.201. The portion of the output of the pump 201 that is not bypassed as aforesaid, is delivered through the line 2|6 and the valve 2 |1 to the ow divider 2 I8, whence it proceeds to the individual burners. The position of the valve 223 will determine the relative portions of the output of the pump 201 that are bypassed through the line 2|5 and delivered to the burners through the line 2|6. The position of the valve 223 is determined by the pressure of fuel above the valve piston section 225, which is by the difference between the pressure existing in the line 204 leading to the pumps 201 and 2| 8 and the pressure in line 242, with the aid of the coil spring 239. If it be assumed that the pressure in line 242 is constant (and this is generally the case) then the greater the pressure in the line 204, the lower the position of the valve 223, the more the piston valve section 225 covers the ports 221, the less the amount of output by the pump 201 bypassed through the line 2|5 and the sleeve valve openings 221, and the greater the amount of the output of the pump 201 going through the line 2|6 to the flow divider 2|8 and to the openings. Thus there is a tendency to maintain the constant pressure in the line 204 or on the intake side of the pumps 201 and 208, for the greater this pressure becomes, the greater the relative amount of the pump output delivered to the burners. If pump 201 fails,

presumably the output pressure of the pump falls very low, and the fuel pressure on the intake side reaches a high level. Consequently, two things happen: pump 208 delivers fuel through line 234, check valve 236, and lines 213, 2H, and 2I6 to the iiow divider 2 I8; and the piston valve 223 is depressed under the increased fuel pressure in the line 204 until the sleeve valve openings 221 are completely closed, and the sleeve valve openings 231 are at least partially closed, thereby reducing the amount of fuel bypassed from pump 208 by way of line 235 and return line 229. If pump 201 again functions properly. pressure in the line 204 will be sufficiently lowered as a result of fuel delivered by pumps 201 and 208 to cause the piston valve 223 to rise until the output of pump 202 is bypassed by virtue of complete uncovering of the valve openings 231, and a portion of the output of pump 201 may be bypassed by a partial uncovering of the valve openings 221.

The term air when used in the claim is intended to mean any appropriate combustionsupporting medium.

Iclaim:

In combination, in a gas turbine power plant, a burner for the gas turbine for supplying gaseous products of combustion of fuel and compressed air thereto, means forming a path for the flow of fuel to the burner, means forming a path for the iow of compressed air to the burner, means forming a regulating orice in said fuel path, means forming rst and second metering orices in parallel with one another in said fuel path, means associated with the metering orices for making a measurement of the fuel-flow rate in the fuel path, means for making a measurement of the air-ow rate in the compressed air path, means responsive to the relation of the two just-.named measurements for adjusting the regulating orice to maintain a predetermined ratio of fuel-now rate to air-flow rate at a given temperature of compressed air flowing to the burner,

.a temperature-sensing element for producing an electrical signal and being interposed at the entrance to the burner in the compressed air path, a restrictive member in the iirst metering orice for adjustably restricting the first metering orifice, an electrical amplifier device having automatic means for adjusting the position of said restrictive member in the first metering orice and being actuable by the electrical signal from the temperature-sensing element to increase the restriction and thereby increase the leanness of the fuel/air ratio in response to increase of compressed air temperature, a manually operated valve in the second metering orice for adjustabiy restricting the second metering orifice, and manually set means having indicia and being connected to the valve for adjusting the restriction of the second metering orice directly in order to select the desired tempera= ture of combustion products as indicated by the said indicia so as to produce diiferent predetermined values of temperature of combustion products.

PAUL W. WYCKOFF.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,370,532 Fulton Mar. 8, 1921 2,219,994 Jung Oct. 29, 1940 2,378,036 Reggio June 12, 1945 2,384,282 Chandler Sept. 4, 1945 2,400,415 Hersey May 14,1946 2,405,888 Holley Aug. 13, 1946 2,414,322 Mock Jan. 14, 1947 2,440,241 Armstrong Apr. 27, 1948 2,447,261 Mock Aug. 17, 1948 2,447,265 Beardsley Aug. 17, 1948 2,447,267 Mock Aug. 17, 1948 2,457,595 Orr Dec. 28, 1948 2,486,223 Stresen-Reuter Oct. 25, 1949 

